The Data-Over-Cable Service Interface Specification (DOCSIS) was established by cable television network operators to facilitate transporting data traffic, primarily Internet traffic, over existing community antenna television (CATV) networks. In addition to transporting data traffic, as well as television content signals over a CATV network, multiple services operators (MSO) also use their CATV network infrastructure for carrying voice, video on demand (VoD) and video conferencing traffic signals, among other types.
The growing traffic demand and competition are the main drivers that push the MSOs to offer more bandwidth to their subscribers. Deploying more DownStream (DS) and UpStream (US) channels can be expensive and can therefore put the MSOs at competitive disadvantage. The US spectrum is scarce and the US processing is complex, largely because of the US scheduler, which has to coordinate transmissions of all the users on all the US channels. The complexity of the US scheduler involves a lot of processing power and therefore contributes heavily to the cost of the US channels, which are normally more expensive than the DS channels. Developing a simplified and more effective US scheduler can result in offering more US bandwidth at lower cost.
An example of a simplified US scheduler includes a scheme where only a single Cable Modem (CM) is scheduled at a time for transmission on all US channels. No matter how many US channels or CMs exist in the system, the US scheduler will stay simple. When all CMs have large amount of data to transmit, this simple, efficient, and cost-effective US scheduling algorithm provides an average latency that is comparable to the average latency found in sophisticated US schedulers currently employed in the Cable Modem Termination Systems (CMTSs). However, one disadvantage of this algorithm is that when some CMs have small amount of data for US transmission (e.g., BW requests, station maintenance, voice packets, acknowledgment packets, etc) then they may undergo higher latency than average, which will negatively affect their service. Thus, there is a need for improved upstream scheduling.
Like details in the figures such as reference numbers generally refer to similar, but not necessarily identical features.